Every day at cheese factories in northwestern Wisconsin, tanker trucks haul away thousands of gallons of wastewater. Much of it is taken to nearby farms, where it is sprayed across the fields as fertilizer.
The waste is high in nutrients like phosphorus and nitrogen. If it runs off the fields into nearby lakes and rivers, it can cause unhealthy amounts of algae in the water.
GreenWhey Energy, a new company in Turtle Lake, is now taking some of that waste, removing much of the harmful material, and using it to generate electricity.
Balancing act
Cheese is a big deal in Wisconsin. The state produced 2.8 billion pounds in 2012, more than any other state. It is home to almost twice as many cheese factories as New York, the next state on the list.
Lakes and rivers are important here too. The northwestern part of the state is home to the nationally-recognized Wild & Scenic St. Croix River and many other beloved lakes and rivers.
It’s been difficult to keep the peace between cheese and clean water.
Algae bloom in the St. Croix River in August 2013 (courtesy MN DNR)
“Phosphorus and nitrogen are both limiting nutrients for algae, so when they wash into streams or rivers they have a tendency to produce algae blooms,” says Michelle Balk, a wastewater engineer with the Wisconsin Department of Natural Resources.
Not only does the waste feed algae, but it depletes oxygen in the water. As it decomposes it consumes oxygen, harming fish like trout that need a lot of oxygen in the water.
The challenge of preventing that harm is amplified by unique aspects of northern Wisconsin.
The DNR only allows the spreading of wastewater on fields with low enough slope to reduce runoff risks, far from lakes and streams, and with a good distance to bedrock and groundwater supplies below.
In hilly, water-rich northern Wisconsin, where the bedrock is near the surface because the glaciers scraped the land clean, fields like that are in short supply. Adding to the challenge, because spreading waste in the rain or on frozen fields increases runoff, the DNR recently started prohibiting the practice.
From problem to opportunity
The cheese producers’ big competitors in California are all large enough to have their own wastewater treatment plants, but most little factories in Wisconsin can’t afford such an expense.
“We’re a small manufacturer. We had looked at a system for our plant, but we didn’t have the volume for the capital expenditure,” says Tom Messicci at Comstock Creamery.
As the problem grew, a few cheese industry veterans came up with an idea.
GreenWhey Energy was founded in 2009 by longtime cheesemaker Tom Ludy and father-son duo of Larry and Tim Peaster, who operate a business hauling liquid waste from cheese factories and other food producers.
Using technology developed by St. Paul-based Ecolab, Greenwhey feeds the waste to a 4-million-gallon tank full of microbes. As they consume the nutrients, the “digesters” expel methane and other gas. That gas is used to power generators which can produce enough electricity to power about 3,000 homes.
“We’re removing about 1,000 pounds of phosphorus from the wastewater everyday,” says Eric Ludy, Quality Assurance Manager at GreenWhey.
How wastewater is converted to energy and fertilizer (Courtesy GreenWhey)
The plant started operating in August 2013 and is only at about half-capacity so far. The company needs to slowly build up the microbe population the tank. And it needs more wastewater from more factories.
First of its kind
GreenWhey was the first company in the United States to take waste from multiple sources and converting it to energy. While an individual plant like Comstock Creamery isn’t big enough, and doesn’t produce enough waste, to justify building its own plant, GreenWhey makes it work by treating the waste from factories throughout an approximately 30-mile radius.
This could mean more cheese, more clean water, and less need for fossil fuels. Greenwhey has the potential to solve a problem for lakes and rivers, businesses, and communities, says Deb Ryun, executive director of the St. Croix River Association.
“I think it’s promising anytime an industry finds innovative ways to do business and do their part to protect water,” Ryun says.
When in full swing, GreenWhey also plans to have leftover solid waste which can be sold as lawn fertilizer. At this point, they are still sending some waste to the Turtle Lake’s wastewater treatment plant.
With a population of about 1,000 people, it’s foreseeable that someday most homes in the town could be powered by cheese. And the local fish might breathe a little easier, too.
Note: This story has been updated to reflect that GreenWhey is not the only company in the United States accepting waste from multiple sources.